Re:Book Review: The Body Keeps the Score
by bobcostas55 on Wednesday November 13, 2019 @08:53AM
(#21523957)
There's no such "time scale", it all depends on the strength of the selection. Lactase persistence went from zero to ~100% in some populations in less than 3000 years.
Re:Book Review: The Body Keeps the Score
by patrec on Wednesday November 13, 2019 @09:33AM
(#21524486)
Exactly -- Lactose tolerance is a common counter example to the strange notion that evolution in humans has somehow stopped either literally or practically (given supposedly glacial timescales).
Re:Book Review: The Body Keeps the Score
by chrisweekly on Friday November 15, 2019 @08:22AM
(#21544521)
You're both right, of course. I was thinking in terms of evolutionary psychology and neuroanatomy -- areas where the timescales are "glacial" compared to the rise in lactose tolerance over a handful of generations.
Re:Book Review: The Body Keeps the Score
by bobcostas55 on Friday November 15, 2019 @08:32AM
(#21544592)
There's nothing inherently slow about selection on psychological traits. To give just one striking example, there is extremely rapid selection against intelligence in advanced societies going on right now, at a rate of about 0.25-0.3 standard deviations per century.
US: https://www.pnas.org/content/suppl/2016/05/25/1523592113.DCS... (Table S11)
Taiwan: https://www.sciencedirect.com/science/article/abs/pii/S01602...
Iceland: https://www.dropbox.com/s/9vq5t6urtu930xe/2017-kong.pdf
In terms of selective adaptation, isn't the time scale for human evolution more like 40-50,000 years? IOW, biologically, aren't we living humans the result of evolutionary pressures that predominated in our distant ancestors' lives on the savannah?